Synthetic as well as natural agents have been used for cleansing purposes. Soaps, surfactants and synthetic detergents have been used for decades for skin and hair cleansing. The objective of cleansing is to remove surface dirt, makeup, the top layer of dead skin cells and potentially harmful microorganisms.
Soaps are made by reacting oils with alkali and are very efficient in removing dirt by emulsification. Unfortunately, there are two problems with soaps: drying; and irritation of the skin due to excessive cleansing action and increased pH of the skin. Surfactants are typically synthetic compounds or materials which are good emulsifiers, but may be harsh to the skin. Synthetic detergents generally offer a better choice because their pH may be adjusted to that of skin, but again they may dry the skin too much and cause irritation. Both soap and the surfactants may be irritating to the eyes and may cause allergic reactions in some people. In addition formulations containing soap or surfactants typically provide little or no exfoliating or moisturizing effect, thus requiring the use of a separate exfoliant formulation and a moisturizing lotion or cream.
Natural agents used for cleansing include, for example, Shikakai (Acacia concinna), Soapwort (Saponaria officinalis) and/or Ritha (Sapindus mukorossi). These plant products have powerful saponins and are good cleansers, but they suffer from the same disadvantages of soap and synthetic surfactants, namely, skin and eye irritation. They may also be poisonous. For example, when ingested in excess, Soapwort destroys red blood cells and causes paralysis of the vasomotor center.
Another traditional method of cleansing, without the use of soap or a synthetic surfactant, involves rubbing the body with a vegetable oil, such as, for example, sesame oil, coconut oil or the like, followed by rubbing with a paste made from a grain flour. Such grain flours may, for example, be derived from Black Gram (Vigna mungo), Green Gram (Vigna radiata), Soy (Glycine max), Basan and/or Chickpea (Cicer aerientinum) and are typically or commonly combined with water and/or milk to form the paste. However, this method suffers from many disadvantages: (1) the paste of flour with water is susceptible to microbial growth and is physically unstable, requiring preparation of the paste just before use; (2) by making an aqueous paste of the grain flour, the exfoliant properties will be lost because the grain flour loses its grain structure and strength in aqueous media; (3) the flour paste requires a preservative system because it is an aqueous system, however, such preservatives can cause allergies; and (4) it is not possible to control the proportion of cleansing, exfoliating and moisturizing actions with such a method.
Thus, there is a need for stable personal care formulations containing no soap or a synthetic surfactant, providing simultaneous exfoliant, cleansing and moisturizing actions, requiring no preservative system, lending themselves to balancing the proportion of cleansing, exfoliant and moisturizing actions and not being irritating to the eyes.